1. Field of the Invention
The present invention relates to a method of manufacturing an imaging device.
2. Description of the Related Art
To decrease resistance of a source/drain and/or a gate electrode of MOS transistors in imaging devices, a technology of forming a metal compound layer thereon is known.
Japanese Patent Application Laid-Open No. 2013-145853 discloses forming of a protective layer that covers a photoelectric conversion unit to form the metal compound layer.
In Japanese Patent Application Laid-Open No. 2013-145853, the protective layer and an insulating layer that is a lower layer of the protective layer are layered in a pixel region (pixel circuit unit). Meanwhile, the protective layer and the insulating layer are removed in a peripheral circuit region (peripheral circuit unit). Therefore, a difference of elevation is caused between the pixel region and the peripheral circuit region. It is difficult to resolve influence of such a difference of elevation even if applying planarization processing to an insulator film that covers, from the pixel region to the peripheral circuit region, the insulating layer and the protective layer that cause the difference of elevation.
Unevenness caused in an upper surface of the insulator film due to the influence of the difference of elevation may cause formation defect of a member such as wiring formed on the insulator film, and become a cause to decrease a manufacturing yield.